A photo posted on Twitter by Uber Entertainment's Chandana Ekanayake shows a t-shirt with a Half-Life 3 logo, saying: "All I'm saying is I saw this at a local game developer event worn by a Valve employee." Whether this is significant, or just trolling is not clear yet. The two hash tags he uses for this are #HalfLife3 and #ValveTrolling. Thanks Computer and Video Games.

Unfortunately I can't track down the interview, but I distinctly remember Gabe being asked at what point in the dev process the next HL was in, and he said they were still in the concepts and ideas phase. That lead me to believe that they were still just tossing ideas around for how to make the next game blow our minds, but weren't actively designing it.